Got Milk? A Question about cows and milk production...

Ok, I’ll admit right off the bat that I am naive about livestock and the farm life - and to tell you the truth, I feel a bit silly for asking this but I just gotta get the facts.

Considering that in human females milk production usually only coincides with pregnancy and birth and evenually will cease when the milk is no longer needed, what is the story with dairy cattle?

Can I safely assume that for dairy cattle to produce milk then they must have given birth to at least one calf and because the milk is continually extracted they keep producing it? Or are dairy cows able to produce milk regardless?

Furthermore, what is the “useful service life” of a dairy cow? i.e., how long can a single cow produce milk?

For those of you smart alecks on this board - no I DON’T have an unhealthy facination about cows and mammaries. This question is just one of those things that I continually wonder about. Thanks for getting that straight! :slight_smile:

A lot of times, dairy cows are given hormones that allow them to produce milk far longer than they normally would. Naturally, however, bulls are often given time for extended conjugal visits with quite a number of cows. So yes, they are kept in a constant state of milk production through birth.

Also, it should be noted that one bull can manage to service quite a number of cows. Bulls are quite ahem resilient creatures.

I imagine so! Kinda like teenagers in that sense huh.

From a trip to a large dairy farm in Lancaster I made 4.5 years ago:

Avg. years of milk production from cows: 3-5

Hormones can and are used to extend the length of a milk-producing period. But the farmers told me that, generally, the maximum volume of milk that each cow can produce in its lifetime is no different. With hormones, they just produce it all in a much shorter period of time than they used to, and are then sold off to the Beef and Leather people.

Once they reach producing age, cows are generally kept milking by being constantly kept pregnant and forced to churn out more calves. And, as Enderw24 pointed out, such techniques are supplemented with hormones and antibiotics.

I’m not sure how important bulls are any more. I went to an agricultural high school that had a dairy herd, and the cows were generally made to reproduce using artificial insemination. The semen obviously has to come from bulls in the first place, of course, and it’s an amazing process to watch.

The bull either mounts a real cow or a constructed dummy, and the farmer/vet redirects the penis into a catching device to collect the semen. There is also a procedure whereby a probe is inserted into the bull’s anus and a small electrical charge is pased through it, causing ejaculation. At least these are the methods that i saw in high school in the mid-1980s; things may have changed since then.

Never bother a dog while he’s eating his supper.
So, um, what’s the life expectancy of a vet who tries either of these stunts? And which genius decided this was a good idea?
“According to my hypothesis, if we just take these broken electrical cords, plug them in, and shove them up ol’ Burro’s anus while he’s riding Bessy, he should enjoy it quite splendidly. In theory.”

::Other scientists look at each other across the table.::

“Not it!”
“Not it!”
“Not it!”
“Not it!”

Boy, how would that look as a term paper or thesis?

“Electrical anal implants and their uses in modern livestock breeding…”


A related question I have always wondered is what happens to dairy cows after they have outlived their usefulness? Are they slaughtered just as cattle are and become hamburger or is their meat somehow different and not used for beef production? Anyone know?

Usual time system involved without the use of hormones is that a cow has her first calf at 2 to 3 years of age. For instance if a cow has her first calf 1/1/01 nwe will try to breed her again around 4/1/01 then dry her off a (stop milking her) at the end of second trimester 10/1/01 then she will have her next calf at around 1/1/02.

If Antibiotics are administered then the milk can’t be used for consumption for a certain period so it is not often used to increase milk production unless the cow is sick. mhendo might be referring to beef and other meat production where growth is the major factor.

I don’t have any first hand information on hormones since we don’t use them and our bottler doesn’t allow its’ use. From information I’ve read it extends the lactation period so that a farmer can breed them later or not breed them back at all and just milk the cow for one long lactation, though this seems to only add 3-6 months onto the lactation production stays fairly high for that extended period.

I used to work in a dairy farm, and this is what I remember: The cows do need to become pregnant and give birth before they will start to lactate. Actually, the milk of a first time mother isn’t so great – they haven’t been exposed to many antibodies yet – so we would mix their milk with the milk of older mothers to feed the calves.

Unlike people, cows can continue to provide milk well into their pregnancy. We would “dry out” the cows a few weeks before they were supposed to give birth.

They will continue to lactate for a long time after giving birth (I believe the milking process triggers that), but after a while the quality of the milk will go down.

While most cows by us would last around five years, some cows last much longer, and I know of one cow that continued for nearly 20 years.

Here are a few cow related links I still have in my bookmarks:

So the quality of the milk relates directly to how long the cow has been milked?

Interesting. I think that we about have this one nailed down.

Thanks, everyone, for all of your replies.

As to the quality declining as lactation lengthens it depends on how you measure it. Butterfat seems to decline the most, Protein and the other solids fluctuate less, but it doesn’t get below what whole milk in the store is. This came up on the boards several months back and I did some research into the butterfat numbers. Whole milk in the stores runs 3.29 (that’s homogenization for ya) while the average milk coming from the farm was running around 3.5 IIRC (you should be able to find the previous thread, along with manny others, through the search function). Even when we have a high percentage of cows in the barn towards the end of their lactation cycle, the butterfat tests usually don’t fall below 3.45. When we have a lot of cows early in their lactation the tests run as high as 3.60 or higher.

Now once we ship our milk to the milk handler things change. They will combine the milk coming in, remove some of the butterfat and pasteurize as well as add whatever else they’re fortifying (vitamin A, D). Thus the resulting Whole milk you buy in the store will taste about the same week after week. Average Butterfat in the milk from the farm will almost (never say always) always be higher than that found in the stores. So the natural fluctuation in the butterfat numbers (which is the primary measure of quality) through the length of the lactation is going to be higher at its’ lowest point than the whole milk on the store shelves since butterfat is removed down to the 3.29 during milk processing.

Did any of that make sense (sometimes I’m terrible at explaining this stuff) ?

To funneefarmer:

Perfect sense, although i would add a caveat. I seem from remember from my high school agriculture classes that butterfat levels differed quite dramatically among breeds of dairy cattle, with the breeds that yielded higher milk volumes (e.g. Holstein-Freisian) tending to have lower butterfat, on average, than breeds such as Jersey and Guernsey, which gave less milk.


            Originally posted by curwin

** They will continue to lactate for a long time after giving birth (I believe the milking process triggers that), but after a while the
quality of the milk will go down.
This is not true. Quantity of milk goes down, but rarely if ever to zero. Older cows are replaced becuase the younger ones are better (more efficient) producers.
Also, a couple other points :
Antibiotics are used for treatment of diseases, but these cows are segregated and their milk is NEVER allowed to go into the tank. Each and every shipment of milk is tested, and if they are detected, the milk is dumped, and the farmer gets a bigass fine; if it happens twice, they’ll stop taking his milk (ie he’s out of business).

Another thing, regarding the meat. Chances are the hamburger you got at McDonalds, or any beef for that matter, is from a culled dairy cow. Unless specified (like “100% angus beef”) most (maybe 90%) of the beef eaten in the US is dairy beef.

I was always under the impression that the only cattle used for meat products (with the exception of veal) would be males who were castrated as so the onset of hormones does not toughen the muscles. I could be wrong, but I don’t think old dairy cows are ever slaughtered for meat.
Please correct if wrong.

well, i guess my question was answered in the post right above my original one. thanks.

That is a very interesting comment regarding average butterfat. Here in Japan (where I live) the average whole milk sold off the shelves is about 3.6 - 3.7. You can also pay an extra buck if you want 4.0 - 4.4 percent as well. On the other end of the spectrum, I think the average Japanese low fat milk is around 2.2 percent. Personally, I like the taste of the 4.0 milk.

Yes we’re talking Holsteins on this farm and I would think that they make up the majority of production in North America. Jersey and Guernsey run a higher butterfat but their production numbers per cow are a little smaller.



Note : After looking at many websites giving average butterfat and production numbers, none of them seem to agree but this gives you a general idea.

hashiriya, it wouldn’t surprise me a bit to find that different cultures have different tastes in milk and that the companys are willing to add butterfat or use higher butterfat producing breeds to cater to those tastes.

Also remember that modern cows lactate so much because they’ve been bred for it for thousands of years. Your average wild cow would lactate only while the calf is nursing, not for virtually all her adult life.

So, you can milk other mammals…horses, buffalo, llama, etc, but you won’t get very much milk without a couple thousand years of selective breeding.

BTW, anyone know if the Incas ever used llama milk?

I’m a guy, and once, out of curiousity, I <squeezed> one of my nipples…I SWEAR a few micro-drops of milk came out. Either that, or there’s something SERIOUSLY wrong with me.